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Full-Text Articles in Metallurgy
Modifying Casting Parameters To Improve The High Temperature Ductility Of Investment Cast Nickel-Based Superalloy Pwa 1455, Lars Alexander Hedin, Cole Magnum Introligator
Modifying Casting Parameters To Improve The High Temperature Ductility Of Investment Cast Nickel-Based Superalloy Pwa 1455, Lars Alexander Hedin, Cole Magnum Introligator
Materials Engineering
PCC Structurals, an industry leader in superalloy investment castings, has observed inconsistencies in the stress rupture performance of polycrystalline nickel-based superalloy PWA 1455. PCC has changed their casting parameters to reduce the thermal gradient during cooling but have been unable to correlate these changes with an increase in stress rupture elongation. Metallographic examination of past samples indicated microstructures composed of non- equiaxed dendritic grains with mean diameter of .021 inches along the test axis. A similar study on polycrystalline superalloys has indicated that excessive superheat temperatures above the liquidus can result in large grains identical to those observed, limiting the …
Development Of Low Cost Braze Alloys For Aerospace Applications, Alyssa M. Elliott, Sandy Babich, Blake Whitmee
Development Of Low Cost Braze Alloys For Aerospace Applications, Alyssa M. Elliott, Sandy Babich, Blake Whitmee
Materials Engineering
Non-precious metal braze alloys can help lower the cost of brazing, which is a commonly-used joining process in the aerospace industry. A-286, a stainless steel superalloy, and Inconel© 718, a nickel-based superalloy, are both commonly used alloys at Aerojet Rocketdyne. Both alloys were brazed into butt joints using nickel-based braze alloys: AMS 4776, 4777, and 4778. The brazed samples were machined into a modified version of the ASTM E8 subsize specimen samples and tensile tested to compare the strength and calculated elongation of the brazed samples to the base metals’ properties. All of the brazed samples fractured at the joint, …
Dissimilar Metal Weld Variability Due To Lot Differences In Nitinol/ Stainless Steel Interface, Matthew R. Rudow
Dissimilar Metal Weld Variability Due To Lot Differences In Nitinol/ Stainless Steel Interface, Matthew R. Rudow
Materials Engineering
Abstract
An experiment was conducted to determine and reduce the causes of variation between a 304 Stainless Steel and super elastic Nickel Titanium dissimilar metal weld. Six factors were established to understand the cause of variation: perpendicularity, final grind, surface finish, weld force, weld pulse duration, and alignment. Using a rotational test with an air piston break pressures were established and charted in Minitab to identify trends. It was shown that weld force and weld pulse duration were the two factors that had the most influence on break strength. This data also showed that higher strength groups had less variability. …